Calling Code Lookup Skill

Overview

A country calling code API for phone inputs, signup forms and SMS routing. Pass a two-letter ISO country code such as FR and get its calling codes (+33), common name and official name; calling codes come back as an array because some countries use more than one. Add dialing=true for the international (exit) prefix on every plan. Paid plans add the region and subregion, and in the dialing block the national trunk prefix, the other countries that share the calling code, valid number lengths and example numbers for fixed-line, mobile and toll-free lines, taken from Google's libphonenumber metadata. To check whether a specific number is valid, use Phone Number Validator.

Live Test Calling Code Lookup Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as CallingCodeLookupSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

{
  "name": "CallingCodeLookupSkill",
  "arguments": {
    "country": "FR"
  }
}

You do not name the tool yourself; the model picks it. Asking about FR in the terms this skill covers is enough for it to reach for CallingCodeLookupSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

https://api.vervekit.com/v1/mcp

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

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{
  "status": "ok",
  "error": null,
  "data": {
    "country": "France",
    "officialName": "French Republic",
    "countryCode": "FR",
    "callingcodes": [
      "+33"
    ],
    "region": "Europe",
    "subregion": "Western Europe",
    "dialing": {
      "internationalPrefix": "00",
      "nationalPrefix": "0",
      "sharedWith": [],
      "possibleLengths": {
        "fixedLine": [
          9
        ],
        "mobile": [
          9
        ],
        "tollFree": [
          9
        ]
      },
      "exampleNumbers": {
        "fixedLine": {
          "international": "+33 1 23 45 67 89",
          "national": "01 23 45 67 89",
          "e164": "+33123456789"
        },
        "mobile": {
          "international": "+33 6 12 34 56 78",
          "national": "06 12 34 56 78",
          "e164": "+33612345678"
        },
        "tollFree": {
          "international": "+33 801 23 45 67",
          "national": "0 801 23 45 67",
          "e164": "+33801234567"
        }
      }
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

A call costs 1 credit each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Signup Form Prepopulation

When users pick their nationality on signup forms, frontends populate the international phone prefix automatically to avoid input errors.

Contact Record Normalization

Clean customer address books by appending verified country dialing prefixes to local phone numbers stored with ISO country codes.

SMS Gateway Routing

To dispatch two-factor authentication alerts, messaging systems verify recipient phone prefixes against their registered account country.

Logistics Contact Sheets

Shipping platforms convert destination ISO codes into international dialing prefixes so couriers can contact international package recipients.

Other ways to use Calling Code Lookup Skill

Set up Calling Code Lookup Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Related

More in Data Lookup: